1. Field
Example embodiments of the present inventive concept relate to methods of sensing touches.
2. Description of the Related Art
A touchscreen is a display screen having an input device that senses a touch by, for example, a finger of a user or an object (such as a stylus). Recently, as electronic devices have become smaller, a more simple and a more direct input technique for interacting with electronic devices have been desired, and thus, the touchscreen has become widely used as an input/output device of a flat panel display device.
Typically in the touchscreen, a touch panel and a display panel are integrally formed. The touch panel may determine a presence and a position of a touch input by sensing contact by a user. The display panel may be one of various display panels, such as an organic light emitting display (OLED) panel, a liquid crystal display (LCD) panel, a plasma display panel (PDP), a cathode ray tube (CRT) panel, etc.
The touch panel may be classified into a capacitive type touch panel, a resistive film type touch panel, an infrared type touch panel, etc. according to an input sensing manner. A conventional touch panel senses only a single touch. However, a capacitive type touch panel capable of sensing a multi-touch has been recently developed.
The capacitive type touch panel may be classified into a self capacitive type touch panel and a mutual capacitive type touch panel. The self capacitive type touch panel may detect a change in capacitance at each electrode, and the mutual capacitive type touch panel may detect a change in capacitance at each node between two electrodes having an insulator therebetween. The self capacitive type touch panel may sense the touch by measuring a current flowing through the electrode, and the mutual capacitive type touch panel may sense the touch by measuring the capacitance change at each node.
However, the capacitive type touch panel cannot detect a pressure of a touch input by a user or an object. Thus, to allow various types of inputs for the touchscreen, a pressure detecting touchscreen that detects the pressure at the touchscreen has been developed. The pressure detecting touchscreen may be classified into a resistive film type pressure detecting touchscreen and a capacitive type pressure detecting touchscreen.
The capacitive type pressure detecting touchscreen detects the pressure by employing an additional sensor for detecting the pressure on a lower surface of the mutual capacitive type touch panel. By this configuration, the capacitive type pressure detecting touchscreen may detect the pressure at a touched position. Compared with the mutual capacitive type touch panel that detects a position of a touch input, the pressure detecting touchscreen has an advantage that it is relatively insusceptible to noise, but it may not detect an exact position of the touch input.